Centrifugation as a mean for accelerating sedimentation of cells, particles and precipitates as well as for separation of liquids or cells with different density has long been an integral part of chemical and biochemical protocols.
Two-dimensional centrifugation is generally obtained in an apparatus that performs rotation of the individual cartridges around one axis, while these cartridges are being rotated by separate means around another distal axis.
U.S. Pat. No. 4,883,763 (Holen et al.) discloses a sample processor card formed of a substantially closed chamber which includes a supply of reagent therein. The card includes inlet means for supplying a sample to the card, capillary means communicating with the inlet means to receive a sample supplied to the card and overflow means communicating with the capillary means to receive excess sample which is advanced from the inlet means through the capillary means under the influence of centrifugal force applied to the card in a first direction. The card also includes holding chamber means adapted to receive reagent from the reagent supply and sample from the capillary means in response to centrifugal force acting on the card in a second direction, and cuvette means communicating with the holding chamber means which is adapted to permit the measurement of the chemical reaction between the reagent and the sample. By use of the sample processor card, flow of the reagent and the sample within the card is supposedly achieved solely by centrifugal force acting in two or more directions on the card as the card is subjected to high centrifugal forces in a centrifuge.